We need to stop using inventory - what adjustments do i make to zero out all the inventory?

How do I make sure that my COGS is correct based on what I paid to my vendors?

The office girl entered all the bills incorrectly. She entered the cost for the entire invoice on 1 item the rest of them she put in at a zero cost. 


I just started trying to help the owner out and I am not great at inventory. The owner no longer wants to use inventory. Except to do a count at the end of the year and enter a value for the product still on site at the end of the year for tax purpose.   I think I know how to do that one but not entirely sure. 


I need to zero out all the inventory accounts and adjust the COGS and the Asset accounts. 


After I fix this mess - all AP bills are going to be put in hitting the COGS accounts. Items sold will be set up as a service/sale or Non Inventory Part and hit a income account (That matches the COG account like Item - 125patch will be a Non inventory item and hit a Income Account for Patches and the COGS will be also called Patches.  There will be asset account that matches but the value will be booked at the end of the year adjusting the COGS because those items won't be sold yet.   


I know many will say inventory should be used but the owner is now dead set against it and I need to clean this all up and fast because she needs to present a P&L and Balance sheet to her bank by the end of Oct 2019 and I have to fix this for the past 10 1/2 months . the P&L is so wrong